The
I-69 Advisory Committee Report and Recommendations, combining information from the five segment committees (and current to November 5, 2012), has been posted on the TxDOT website. It has several interesting maps included at the end of the report, including a map combining the priorities of the five committees (page 25/30 of pdf; page 19 of document):

The text on the map identifies "US 59 from the Mexico Border to East of Laredo" as an upgrade priority, but the map itself seems to identify
Loop 20 from the Mexico Border to East of Laredo as a priority.
editOr they could pull an I-10 in west Texas and keep the at-grades. Why were those allowed to be grandfathered there but not here?
The Report indicates that they will pursue exceptions with FHWA (page 19/30 of pdf; page 13 of document):
The Advisory and Segment Committee members recommend designating existing sections of highway as I-69 when they meet Interstate standards. Committee members also encourage TxDOT to work with FHWA to gain exceptions to some Interstate standards required for portions of highways recommended for I-69 in South Texas, such as highway sections within ranch areas, where Interstate standards today may not be warranted but Interstate designation is still needed.